Mobile tomography imaging

ABSTRACT

A detector used for tomography imaging is mobile, allowing the detector to move about an object (e.g., patient to be imaged). A swarm of such detectors, such as a swarm of drones with detectors, may be used for tomography imaging. The trajectory or trajectories of the mobile detectors may account for the pose and/or movement of the object being imaged. The trajectory or trajectories may be based, in part, on the sampling for desired tomography. An image of an internal region of the object is reconstructed from detected signals of the mobile detectors using tomography.

BACKGROUND

The present embodiments relate to tomography imaging, such as nuclearmedical imaging. For tomography imaging, such as computed tomography(CT), positron emission tomography (PET), or single photon emissioncomputed tomography (SPECT), standalone machines are usually fixed inplace in a dedicated room. In SPECT, gamma camera detectors are planardetectors with about 2000 cm² area and are designed to allow the imagingof clinically relevant features without or only minimal patienttruncation (e.g., a 40×50 cm² detector to axially cover at least bothkidneys and image most of a patient torso). This size, includingdedicating a room to one imaging system, may be costly. Patients areinconveniently brought to the imaging system, which is fixed in place.Some medical scanners have been positioned in a truck so that hospitalswithout a dedicated tomography imaging system may have access to such asystem. The patient is brought to the truck and placed in the imagingsystem fixed in place in the truck. The truck-based or room-based large,single devices, do not adapt to the environment and patient beingimaged.

SUMMARY

By way of introduction, the preferred embodiments described belowinclude methods and systems for tomography imaging. A detector used fortomography is mobile, allowing the detector to move about an object(e.g., patient to be imaged). A swarm of such detectors, such as a swarmof drones with detectors, may be used for tomography imaging. Thetrajectory or trajectories of the mobile detectors may account for thepose and/or movement of the object being imaged. The trajectory ortrajectories may be based, in part, on the sampling for desiredtomography. An image of an internal region of the object isreconstructed from detected signals of the mobile detectors usingtomography.

In a first aspect, a tomography medical imaging system includes aplurality of separate vehicles. Each of the separate vehicles isindependently movable in two or more dimensions and has a detector. Animage processor is configured to generate a two or three-dimensionalrepresentation of an internal region of a patient by tomography fromsignals of the detectors. A display is configured to display an image ofthe two or three-dimensional representation of the internal region ofthe patient.

In one embodiment, the plurality includes three or more of the separatevehicles. The separate vehicles may be drones moveable in threedimensions. The separate vehicles may be wheeled, tracked, or walkingvehicles. In an optional swarm approach, the separate vehicles areself-organizing. The mobility may allow for the separate vehicles totravel from one room to another room to the patient.

In one embodiment, the image processor is configured to control atrajectory of each of the separate vehicles. The trajectories are basedon a sampling pattern for the tomography. In a further embodiment, theimage processor is configured to reconstruct by the tomographyiteratively. The trajectories of the separate vehicles are controlledbased, at least in part, on a previous reconstruction by the tomography.

Various detectors may be used, such as x-ray or gamma radiationdetectors. In one embodiment, the detectors are solid state gamma raydetectors.

For a medical or another embodiment, the display may be an augmentedreality display.

One or more of the separate vehicles or another separate vehicle mayinclude a transmitter. The detectors on the separate vehicles areconfigured to detect energy responsive to a transmission from thetransmitter. In other embodiments, the detectors detect emissions fromthe object, such as detecting emissions from radioactive decay.

In a second aspect, a method is provided for medical tomography imaging.A drone with a detector is moved about a patient. Radiation (e.g., x-rayor nuclear emission) from a patient is sensed with the detector duringthe moving. An image of an internal region of the patient istomographically reconstructed from the sensed radiation. The image isdisplayed.

In one embodiment, the drone moves along a trajectory. The sensingincludes sampling the radiation from different positions of thetrajectory. The trajectory is controlled based on the sampling for thetomographically reconstructing.

The detector is one of various types. For example, a solid-state nucleardetector is used.

Other drones with other detectors, such as in a self-organizing swarm,may be moved about the patient. If the patient moves, the movement ofthe drone may adapt so that the drone moves based, at least in part, onmovement by the patient. The drone or drones may go to the patient(e.g., the drone flies from a first location to a second location wherethe patient is at the second location) rather than requiring the patientto go to the tomography imaging system.

In a third aspect, a tomography imaging system includes a swarm ofmobile detectors. Each of the mobile detectors is independently movablein two or more dimensions. An image processor is configured to generate,by tomography from signals from the mobile detectors, a two orthree-dimensional representation of an internal region of an object. Adisplay is configured to display an image of the object from the two orthree-dimensional representation of the internal region.

In one embodiment, the object is a patient. For PET or SPECT, the mobiledetectors may be drones with gamma ray detectors.

In another embodiment, the mobile detectors of the swarm are configuredto follow trajectories based, at least in part, on sampling for thetomography.

The present invention is defined by the following claims, and nothing inthis section should be taken as a limitation on those claims. Furtheraspects and advantages of the invention are discussed below inconjunction with the preferred embodiments and may be later claimedindependently or in combination.

BRIEF DESCRIPTION OF THE DRAWINGS

The components and the figures are not necessarily to scale, emphasisinstead being placed upon illustrating the principles of the invention.Moreover, in the figures, like reference numerals designatecorresponding parts throughout the different views.

FIG. 1 is tomography imaging system according to one embodiment;

FIG. 2 shows drones for tomography imaging in an example medicalapplication;

FIG. 3 shows drones for tomography imaging in another example medicalapplication;

FIG. 4 shows drones for tomography imaging in an example industrial orsecurity application;

FIG. 5 shows drones for tomography imaging in another example securityapplication; and

FIG. 6 is a flow chart diagram of one embodiment of a method fortomography imaging using mobile detectors.

DETAILED DESCRIPTION OF THE DRAWINGS AND PRESENTLY PREFERRED EMBODIMENTS

Mobile and/or swarm tomography is used in various applications. Forexample, nuclear detectors are used in conjunction with drones or othervehicle(s) to assess the spatial distribution of nuclear sources. Thisscanning may be performed in a medical application, but security,geosensing, and radiation protection applications may use the scanning.

One vehicle or possibly a swarm of (e.g., automated) vehicle(s)transports one or more detectors. Depending on the application, atrajectory is flown to acquire sufficient data for tomographicreconstruction. The scanner adapts to the application and the targetarea or patient in order to run an optimal acquisition e.g. by adaptingthe formation flown. Autonomous, adaptable scanning is provided. In amedical application, the patient does not have to adapt to the scanneras the scanning device adapts to the environment and the patient. Thepatient does not have to lie down on a scanner table but may bestanding, moving, or resting in a hospital bed. The use of drones,robots or any autonomous mobile devices allows the scanner equipment tomove around the object or patient being imaged. The scanner adapts tothe object or patient and environment.

FIG. 1 shows one embodiment of a tomography imaging system. Thetomography imaging system is for any of various applications. Forexample, medical imaging is provided, such as shown in FIGS. 2 and 3.The medical imaging may be SPECT, PET, CT, or other tomography(ultrasound or surgical) imaging system. Diagnostic, theranostic,dosimetry, or surgical support imaging may be provided. As anotherexample, geosensing is provided, such as for sensing the location ofobjects for mining. In another example, security imaging is provided,such as sensing radiation from a person, luggage, building, ship, orvehicle (see FIGS. 4 and 5). In yet another example, an agriculturetomography imaging application is provided, such as for sensingemissions from foliage. As another example, the tomography imagingsystem is used for non-destructive material examination.

Any application for imaging the interior of an object and/or imagingradiation may be provided. A tomography medical imaging system is usedin the examples below, but the tomography system may be used in otherapplications.

The tomography imaging system implements the method of FIG. 6 or anothermethod. A mobile detector is used to move around the object (e.g.,patient) being scanned without requiring a gantry and/or positioning ofthe patient in a bed mounted to the scanner. Radiation from the objectis sensed and used in tomographic reconstruction.

The tomography imaging system includes one or more vehicles 10 withdetectors 12, an image processor 14, and a display 16. Additional,different, or fewer components may be provided. For example, the display16 is not provided. While shown as a separate device, the imageprocessor 14 may be on or part of the vehicle 10.

FIG. 1 shows one vehicle 10. Any number of vehicles 10 may be provided,such as the five of FIG. 2, four of FIG. 3, two, three, or more. Withone detector 12 for each vehicle 10, a plurality of mobile detectors isprovided. 1 to n detectors are held and actively or passivelytransported by 1 to m vehicles 10 where n and m are integers. N equalsm, but may not be equal in other embodiments. A swarm of vehicles 10 maybe used, such as three or more.

Each of the vehicles 10 is separate from other vehicles 10. There is nophysical connection between the vehicles 10. Each of the vehicles 10 maymove independently of the other vehicles 10. Separate housings areprovided. An indirect connection through the ground, wall, ceiling, orair may occur, but there is no direct connection or connection throughan engineered object (e.g., no cable or mechanical linkage).

In one embodiment, the vehicles 10 are drones. Each drone includes abattery for power, transceiver for communication, engine, props orblades 11 for mobility, and the detector 12. In other embodiments, thevehicles 10 are wheeled, tracked, or legged (walkers) for independentmovement. For example, each vehicle 10 includes wheels 11 for mobility,an engine and power source (e.g., battery), transceiver, and thedetector 12. Other robots or robotic vehicles 10 may be used. Aprocessor and/or sensor may be included for autonomous navigation.Guided (e.g., remote control) or user-controlled navigation is used inother embodiments.

One or more sensors for position determination may be provided, such asa camera, range sensor, ultrasound sensor, and/or global positioningsensor. The sensor or sensors are on each vehicle 10, and/or a sensor orsensors detect the position of the vehicles 10 remotely.

In an alternative embodiment, the vehicles 10 have connectors or otherreleasable devices for manual change in position. For example, eachvehicle does not include an engine but does include a magnetic or otherconnector. The vehicle 10 may be repositioned to different locations,such as on walls, floor, or ceiling or other surrounding structure. Theseparate vehicles 10 are positioned for sampling and then repositionedfor further sampling to tomographically image an object.

The vehicles 10 actively or passively move in space, each as a singleindependent device. Passive movement may be provided using gravity. Eachvehicle 10 moves independently, so may move in a different directionthan other vehicles 10. The movement may be in two (e.g., across a flooror the ground) or three (e.g., flying in the air) dimensions.

For movement, the vehicles 10 may be operated individually, in pairs, oras a swarm. Any formation may be used, such as independent trajectorieswith collision avoidance, paired trajectories to follow a same orsimilar orbit, or swarm-based trajectories with randomized or othertrajectories. The vehicles 10 may be self-organizing in a swarm.Alternatively, a processor optimized, predetermined, or other plannedtrajectory pattern is used for one, more, or all the vehicles 10. In anapplication where multiple vehicles 10 operate independently, a swarmintelligence and/or an automatic collision avoidance system may be used.

Since the vehicles 10 are not constrained to a single track or fixedconnection to the floor, ceiling or wall, the constraint for directplanar imaging and using a detector 12 sized to the object is removed.The detectors 12 may be smaller than the internal region to be imagedsince the vehicle 10 may move the detector 10 about the object (e.g.,patient). One or more small detectors 12 with location sensing mayexecute coordinated or controlled acquisition patterns to optimallyacquire data from a much larger field of view for tomographic imaging.

The mobility of the vehicles 10, such as being able to move over tens ormore of meters, allows the vehicles 10 and corresponding scanning tomove to the object rather than bringing the object to the scanner. Forexample, the vehicles 10 travel from one room to another for scanningdifferent patients. The vehicles 10 may travel from storage to apatient. For example, FIG. 2 shows the vehicles 10 as drones followingtrajectories 24 to scan a patient 20 for radiation emission 22. Thepatient 20 is in a hospital bed for the patient 20 (not dedicated toscanning). The drones move to the room with the patient 20 to scan thepatient. FIG. 3 shows another example where the drones move to thesurgical suite or room, allowing both surgery and scanning in the sameroom.

FIG. 4 shows an example in an industrial or security application. Thedrones move to the building 40 of interest to scan the building forradiation 22. FIG. 5 shows an example in a security application. Thedrones move to a person 50 (e.g., a passenger) to scan rather thanrequiring the person 50 to lay down in or stand in a scanner.

The vehicles 10 may include a position sensor to detect positionrelative to each other, the local environment, and/or global position.Alternatively, the position of the vehicles 10 is determined by imageprocessing or other capture of the formation of the vehicles about theobject.

Each or most of the vehicles 10 includes a detector 12. The detector 12detects radiation from the patient. For example, emissions fromradioactive decay are detected. Gamma radiation is detected. As anotherexample, x-ray radiation passing through the patient is detected.

The detector 12 is of any size based on weight and space limitations ofthe vehicle 10. In one embodiment, the detector 12 is 10×10 cm, 5×5 cm,3×5 cm or 5×7 cm, but other sizes may be used. Any shape, such as a flator curved plate that is square, rectangular, or another shape, may beused.

The detector 12 is a solid-state detector, such as being asemiconductor. For example, a CZT or other direct conversion gamma raydetector is used. Other solid-state detector modules include Si, CZT,CdTe, HPGe or similar devices. The detector 12 is created with waferfabrication at any thickness, such as about 4 mm for CZT. Alternatively,the detector 12 is another type of sensor, such as a crystal layer andphotomultiplier tubes.

The vehicle 10 and/or detector 12 may include a semiconductor formattedfor processing. For example, the detector 12 includes an applicationspecific integrated circuit (ASIC) for sensing photon interaction withan electron in the detector 12. The ASIC is collocated with the pixelsof the detector 12. The ASIC is of any thickness. A plurality of ASICsmay be provided, such as 9 ASICS in a 3×3 grid of the detector 12.

The detector 12 may operate at any count rate. Electricity is generatedby a pixel due to the interaction with radiation. This electricity issensed by the ASIC. The location, time, and/or energy is sensed. Thesensed signal may be conditioned, such as amplified, and sent to atransceiver for wireless communication.

A collimator may be included in or by the detector 12. Alternatively, nocollimator is provided.

For PET, SPECT, or other nuclear scanning, the detectors 12 detectemissions from the radioactive decay. For x-ray radiation, the detectors12 detect energy from transmission to or through the patient. Thetrajectory 24 of one vehicle 10 is matched with a trajectory 24 ofanother vehicle 10. One vehicle 10 includes the detector 12, and thevehicle opposite the patient 20 includes a transmitter, such as an x-raysource. For transmission tomography applications, two or more vehicles10 move and operate in unison to be able to form a transmission image ofthe object, material, or human being imaged.

The wireless communications are used to synchronize the clocks of thevehicles 10. One vehicle 10 or a base station provides a master clock towhich the clocks of the other vehicles 10 synchronize. For example, theimage processor 14 has a master clock. Wireless communications are usedto synchronize the clocks of the vehicles 10 with the master clockand/or to determine temporal offset of the clocks of the vehicles fromthe master clock. The synchronization allows for PET imaging to operateon paired events detected by different detectors 12. Unsynchronizedclocks may be used in other embodiments.

The wireless communications are used to transmit detected signals (e.g.,emission or decay events). Each vehicle 10 transmits the detectedsignals, such as the time, energy, and location of detection. Thetransmissions are direct to a master device, such as the image processor14 (e.g., computer, tablet, or workstation hosting the image processor14), or are transmitted to another vehicle 10. Mesh or other distributednetwork communications may be used.

The image processor 14 is a general processor, digital signal processor,application specific integrated circuit (ASIC), field programmable gatearray, graphics processing unit, digital circuit, analog circuit, and/oranother now known or later developed processor for performingtomography. The image processor 14 may be formed from multiple devices,such as an ASIC for pairing events and determining angle of coincidence(e.g., PET), a general processor for tomographic reconstruction, and agraphics processing unit for rendering an image from the tomographicallygenerated representation of the interior of the object. Parallel and/orserial processing may be used. The image processor 14 is configured byhardware, firmware, and/or software.

The image processor 14 is configured to generate a tomographic image,such as a SPECT, PET, or CT image. The counts and the positions on andof the detectors 12 (i.e., positions indicating the lines of response)are used to reconstruct a two or three-dimensional representation of thepatient. The image processor 14 determines the lines of response for themeasurements (e.g., x-ray intensity or emission occurrence with orwithout energy). The image processor 14 is configured to identify linesof response for the signals.

The image processor 14 is configured to tomographically reconstruct atwo or three-dimensional representation from the lines of response. Anytomographic reconstruction may be used. In an iterative process, such asusing forward and backward projection from measurement space to objector image space, a spatial representation of the object is generated byoptimization. The scanner (e.g., vehicles 10) is represented as a systemmodel used in the reconstruction. The image processor 14 determines aspatial distribution based on the signals and the system model. Thespatial distribution is a two or three-dimensional distribution. A twoor three-dimensional representation of an internal region of a patientor another object is generated by tomography from signals of thedetectors 12. The locations of emissions are represented for PET orSPECT, and the locations of density or x-ray attenuation are representedfor CT.

The image processor 14 is configured to generate an image 18 from therepresentation. Volume, surface, or other rendering may be performed fora three-dimensional representation. The three-dimensional distributionis rendered to a two-dimensional image 18 for display from a givenviewing direction. Alternatively, a slice or plane represented in thethree-dimensional representation is used to select data to form atwo-dimensional image 18. For a two-dimensional distribution orrepresentation, a two-dimensional image 18 is generated.

The image processor 14 is configured to control the trajectory 24 forone or more (e.g., each) of the vehicles 10. The control is a directmapping or setting of the trajectories, indirect setting of a value of avariable used in forming the trajectories, and/or indication of desiredsampling locations or time used by the vehicles 10 to form thetrajectories. For tomography, Orloff's sphere sampling may be used tosatisfy the Tuey condition. The trajectories 24 are controlled toprovide sufficient sampling for reconstruction of the representation.The trajectories 24 are based on the sampling pattern (e.g., evendistribution over all or part of a sphere or surrounding shapeconceptually formed around the object being scanned) for the tomographicreconstruction.

Since reconstruction is iterative, the image processor 24 may controlthe trajectories 24 differently at different times. For example, areconstruction may result from under sampling at one or more locationsand/or orientations. The trajectories 24 may be controlled to thenacquire more data or samples for the locations and/or orientationsassociated with under sampling. At least part of the trajectory 24 isbased on the previous reconstruction (i.e., iteration in theoptimization). In one embodiment, a live feed of data (signals) is sentto an acquisition system, and an image of a reconstructed object isdisplayed and possibly reviewed by a person. An operator, who canoversee and possibly drive the trajectories 24 of the vehicles 10 and/ordefine regions of interest, causes the image processor 14 to alter oruse the trajectories 24 to correct any undersampling and/or to increaseresolution. In other embodiments, the image processor 14 controls tocorrect undersampling or increase resolution without user input. An“on-the-fly” reconstruction helps to adapt and drive the trajectories 24being followed by the vehicles 10.

The trajectories 24 are orbits, lines, curves, or other motion over timeabout or near the object. The trajectories 24 may include dwell time,such as holding position at a location and/or orientation (e.g., nomotion as part of the trajectory 24). The trajectory 24 may include oneor more locations with dwell time and may include paths to move betweenthe locations. Alternatively, the trajectory 24 is formed entirely ofnon-zero motion or of discrete locations.

The trajectory 24 may be pre-planned. Alternatively, the trajectory 24is created or planned based on the object size, position, orientation,and/or motion. The values of one or more variables for the object and/orenvironment are used with the desired sampling for tomography tocalculate the trajectories. In one embodiment, the vehicles 10 areself-organizing. Randomization or other approach may be used to createtrajectories 24, such as using a robot swarm approach. The imageprocessor 24 may then guide or cause alteration of one or moretrajectories 24 to sample from one or more needed or under-sampledlocations for the tomography. The randomization may be pseudo random,allowing for constraints or increased probability for desired samplinglocations to be included in the trajectories 24.

The trajectories 24 account for the object position, object movement,and/or environment. The ground or other obstructions (e.g., bed, walls,posts, other people, or furniture) are accounted for in the trajectories24. For example, the trajectories 24 of the vehicles 10 in FIG. 2 areplanned to move about the patient 20 without contacting the floor, bed,or patient 20. The trajectories 24 are planned to have a given distanceor within a range of distances away from the patient 20, to be on aconceptual sphere fit to the patient 20 and accounting for obstructions,and/or change curvature at different portions to account for theorientation of the patient 20. In another example, the patient 20 iswalking. The trajectories 24 account for the change in patient positionin order to sample for tomography by re-centering an orbit or changingcurvature or position based on patient change in position.

The trajectories 24 of the vehicles 10 are planned or incorporatecollision avoidance to avoid obstructions and/or each other. Thetrajectories 24 may incorporate constraints of the vehicles 10, such asbeing speed limited and/or constrained to be on the ground for wheeledvehicles 10.

The scanner formed by the detectors 12 on the vehicles 10 uses themobility of the vehicles 10. The scanner adapts to the object (e.g.,patient) and the environment. Rather than a fixed-in-place scannerrequiring the patient to adapt to the scanner, the scanner uses themobility of the vehicles 10 to adapt to the object.

The display 16 is a CRT, LCD, projector, printer, or other display. Thedisplay 16 is configured to display the tomographic image 18. The image18 or images 18 are stored in a display plane buffer and read out to thedisplay 16. The images 18 may be a sequence of images generated fordifferent iterations in the reconstruction as the sampling is updated. Afinal image 18 may be displayed without display of images prior tocompletion of the scan. The image 18 or images 18 are of the two orthree-dimensional representation of the internal region of the object,so represent a view of the interior of the object. Images representingan exterior view may be generated, such as a view of an agriculturalfield.

In one embodiment, the image 18 is an augmented reality image. Thedisplay 16 is an augmented reality display by showing an image of thepatient augmented with reconstructed data (e.g., an optical image of thepatient with a color, greyscale, or symbol (marker) overlay based on thetomographically reconstructed representation). FIG. 3 shows an examplewhere glasses, virtual reality googles, or other augmented display 16 isworn by the user. Rather than an optical image, the actual view of thepatient 20 by the physician is augmented with a projection or image fromthe scanning. Real time feed of images 18 and reconstructed data to avirtual, mixed, and/or augmented reality displaying device is providedfor the operator (physician, technician) for real time evaluation. Rawand reconstructed data is used for imaging on a monitor display, or anaugmented, mixed or virtual reality device is used.

FIG. 6 shows one embodiment of a flow chart of a method for tomographyimaging, such as medical tomography imaging. Mobile or movable, separatedetectors are used to scan. By controlling the trajectories (e.g.,placement) of the mobile detectors, data for tomographic reconstructionis acquired based on the object and the environment.

The method may be implemented by the system of FIG. 1, the drones ofFIGS. 2-5, or other arrangements. Vehicles with detectors or moveabledetectors are positioned according to trajectories (e.g., placement atdifferent sampling positions) and sense signals from the object. Animage processor or another processor controls the trajectories forsampling used in the tomography. The image processor reconstructs arepresentation of the interior of the object from the signals bytomography. A display screen displays the resulting tomographic image.Other systems or devices may be used.

The acts are performed in the order shown (i.e., top to bottom ornumerically) or other orders. For example, acts 60, 62, and 64 areperformed simultaneously or repetitively. As another example, act 66 maybe performed while act 64 is being performed.

Additional, different, or fewer acts may be provided. For example, act62 is not performed as an active control, but instead the mobiledetectors move independently and sample until a controller determinesthat sufficient information is obtained. As another example, act 68 isnot performed, such as where the image or reconstructed representationis saved to a memory or transferred over a computer network. In yetanother example, acts for user input and control are provided, such asuser change to the trajectories used in act 60.

In act 60, a drone or other mobile vehicle with a detector moves or ismoved. The movement uses the mobility of the drone or vehicle to moveabout the object, such as to orbit a patient, drive around the object,walk around the object, or be placed around the object. The movement isalong a trajectory, such as a sequence of locations for sampling fortomography or a path through locations for sampling. The trajectory isused for sampling radiation from different positions relative to theobject.

Other drones or mobile vehicles with detectors may move relative to theobject being scanned and/or each other. One or more separate detectorsare moved around or near the object to sense radiation from differentlocations and/or angles relative to the object. In one embodiment,multiple drones or other mobile vehicles self-organize as a swarm. Themovement is based on the swarm approach being used, such as randomizedmovement constrained in space, speed, and/or collision avoidance, or aformation (e.g., the number of detectors and/or the spatial relationshipof the detectors to each other).

The movement accounts for the environment and the object being scanned.Obstructions may be avoided. The trajectories may be set to positionwithin a desired range from different locations about the object. Theposition and/or orientation of the object results in differenttrajectories to provide the desired sampling. Where the object ismoving, such as a walking person or a person waving their arms, thetrajectories may be set or altered to account for the motion. Forexample, the drones move based on movement by the patient and thedesired sampling. The movement avoids collision with the moving objectand samples from the desired range as the object moves.

In one embodiment, the mobility of the detectors is used forconvenience. The detectors move from one location to a differentlocation (e.g., a different room) to scan the object. For example,drones fly from a storage room or location of a previous scan to anotherlocation (e.g., a hospital room) for scanning a patient at the otherlocation.

In act 62, a person or processor controls the trajectories based on thesampling for tomographic reconstruction. The control is by pre-planning,active control during movement or placement, and/or control by feedback.The mobile detectors (e.g., drones) are controlled or self-control tosample from the locations and/or at angles to provide for tomographicreconstruction. The dwell time at each location and/or angle, speed ofmovement, path along which to move, and/or other characteristic of theplacement of the detector for sampling in tomography imaging iscontrolled.

The control may be a change in trajectory. The trajectory is altered tofurther sample from a location and/or angle relative to the object, suchas where a reconstruction using tomography shows under sampling. Thechange may be due to an obstacle, change in position of an obstacle,and/or movement of the object (e.g., patient). The trajectory ofmovement is changed to account for the object and environment whileproviding the desired sampling for tomography.

In act 64, the detector on the drone or other mobile vehicle sensesradiation from the object (e.g., the patient). A solid state or otherdetector detects x-rays, gamma rays, photons, or other radiation fromthe object. For example, the patient ingests a radiopharmaceutical or anobject may include a radioactive source. Emissions from decay aredetected. As another example, a transmitter transmits the radiation(e.g., x-ray radiation) through the object, and the radiation as alteredby the object is detected.

The sensing occurs during the moving of act 60. The movement of act 60may include stationary positions during which sensing occurs.Alternatively, the sensing occurs while or as the detector moves with anon-zero speed. The movement may include translation and/or rotation.

For PET, different photons or gamma rays from a same emission may bedetected along a line of response. Timing and energy may be used tomatch the detections as an event. For SPECT, a count of emissions alonga given angle at a given position is performed. For CT, the topogram orprojection in two-dimensions showing the attenuation of x-rays throughthe patient is detected.

The detected events from different sampling locations are counted orcollected. The lines of response or lines along which the differentevents occur are used in reconstruction. The lines of response are basedon the position and/or angle of the detector when the event occurred.The distribution in three dimensions of the emissions from or x-rayattenuation of the object may be reconstructed from the events andcorresponding lines of response.

In act 66, an image processor tomographically reconstructs an image ofan internal region of the patient from the sensed radiation of act 64.The lines of response and events are used to reconstruct a two orthree-dimensional representation of the object. CT, PET, SPECT, or otherreconstruction is used. In an iterative optimization, the locations ofemissions or the attenuation at the locations is determined from thedetected signals. For PET or SPECT, tomographic reconstruction is usedto reconstruct the locations of the radioisotope. For CT, tomographicreconstruction is used to reconstruct the attenuation at locationsthroughout the object.

A spatial distribution representing an exterior of the object or objectsmay be reconstructed. For example, the locations of emissions in anagricultural field is reconstructed. The object being represented isemissions from or transmissions through a patient, building, undergroundmineral deposit, person, luggage, vehicle (e.g., truck, plane, or boat),or other object.

In act 68, a display displays an image. The image processor generates animage from the reconstructed representation. An image fortwo-dimensional display is formed or rendered from the representation.The image may be formed by interpolation, display value (e.g., color)mapping, filtering, and/or other image processing.

The displayed image is a view of an internal plane or volume of theobject. The detected emissions or densities of the object are displayed.For example, a PET, SPECT, or CT image is generated as athree-to-two-dimensional rendering or as a planar image. For gamma rayradiation, the image may represent a spatial distribution of emissions.The result may be a map of uptake in a patient or location in anotherobject of radiation emission. This internal (or external) view of theobject may assist in localizing structure of interest, such as functionin a patient, a radioactive source, a flaw in a material, or otherstructure.

The image is displayed on a display screen. Alternatively, the image isprinted or projected. The image may be combined with a view or otherimage in an augmented reality display, a virtual display, or a mixeddisplay.

While the invention has been described above by reference to variousembodiments, it should be understood that many changes and modificationscan be made without departing from the scope of the invention. It istherefore intended that the foregoing detailed description be regardedas illustrative rather than limiting, and that it be understood that itis the following claims, including all equivalents, that are intended todefine the spirit and scope of this invention.

We claim:
 1. A tomography medical imaging system comprising: a pluralityof separate vehicles, each of the separate vehicles independentlymovable in two or more dimensions, each of the separate vehicles havinga detector; an image processor configured to generate a two orthree-dimensional representation of an internal region of a patient bytomography from signals of the detectors; and a display configured todisplay an image of the two or three-dimensional representation of theinternal region of the patient.
 2. The tomography medical imaging systemof claim 1 wherein the plurality comprises three or more of the separatevehicles.
 3. The tomography medical imaging system of claim 1 whereinthe separate vehicles comprise drones moveable in three dimensions. 4.The tomography medical imaging system of claim 1 wherein the separatevehicles comprise wheeled, tracked, or walking vehicles.
 5. Thetomography medical imaging system of claim 1 wherein the image processoris configured to control a trajectory of each of the separate vehicles,the trajectories based on a sampling pattern for the tomography.
 6. Thetomography medical imaging system of claim 1 wherein the detectorscomprise solid state gamma ray detector.
 7. The tomography medicalimaging system of claim 1 wherein the separate vehicles areself-organizing.
 8. The tomography medical imaging system of claim 1wherein the separate vehicles are configured to travel to the patientfrom one room to another room.
 9. The tomography medical imaging systemof claim 1 wherein the display comprises an augmented reality display.10. The tomography medical imaging system of claim 1 wherein the imageprocessor is configured to reconstruct by the tomography iteratively,and control the trajectories of the separate vehicles based, at least inpart, on a previous reconstruction by the tomography.
 11. The tomographymedical imaging system of claim 1 further comprising a transmitter onone of the separate vehicles of the plurality or on another vehicle, andwherein the detectors are configured to detect energy responsive to atransmission from the transmitter.
 12. A method for medical tomographyimaging, the method comprising: moving a drone with a detector, thedrone moving about a patient; sensing radiation from a patient with thedetector during the moving; tomographically reconstructing an image ofan internal region of the patient from the sensed radiation; anddisplaying the image.
 13. The method of claim 12 wherein movingcomprises moving the drone along a trajectory and sensing comprisessampling the radiation from different positions of the trajectory, andfurther comprising controlling the trajectory based on the sampling forthe tomographically reconstructing.
 14. The method of claim 12 whereinsensing comprises sensing with a solid-state nuclear detector.
 15. Themethod of claim 12 further comprising moving other drones with otherdetectors, the drone and other drones comprising a self-organizingswarm.
 16. The method of claim 12 wherein moving comprises moving based,at least in part, on movement by the patient.
 17. The method of claim 12wherein moving comprises the drone flying from a first location to asecond location, the patient being at the second location.
 18. Atomography imaging system comprising: a swarm of mobile detectors, eachof the mobile detectors independently movable in two or more dimensions;an image processor configured to generate, by tomography from signalsfrom the mobile detectors, a two or three-dimensional representation ofan internal region of an object; and a display configured to display animage of the object from the two or three-dimensional representation ofthe internal region.
 19. The tomography imaging system of claim 18wherein the object is a patient, and wherein the mobile detectorscomprise drones with gamma ray detectors.
 20. The tomography imagingsystem of claim 18 wherein the mobile detectors of the swarm areconfigured to follow trajectories based, at least in part, on samplingfor the tomography.